1. Field of the Invention
The present invention relates to a circuit module which includes a circuit board having, for example, an electric circuit, and which is applied to an electronic device, etc.
2. Description of the Related Art
FIG. 5A is an exploded perspective view schematically showing an example of a circuit module. As shown in FIG. 5A, a circuit module 31 includes a circuit board 3 and a shield case 35. The circuit board 3 has an electronic component 30 mounted on a front surface of a board, thereby forming an electric circuit. The shield case 35 shields the electric circuit of the circuit board 3 by covering a front surface and a side peripheral surface of the circuit board 3. The shield case 35 includes a frame section 32 covering the side peripheral surface of the circuit board 3, and a lid section 34 covering the front surface of the circuit board 3.
The circuit board 3 is arranged in an opening 32a of the frame section 32. In this state, the lid section 34 is provided above the front surface of the circuit board 3 to close the opening 32a at an upper side of the frame section 32. Hence, the lid section 34 covers the front surface of the circuit board 3. FIG. 5B is a plan view schematically showing a positional relationship between the circuit board 3 and the frame section 32. As shown in FIG. 5B, a predetermined clearance (gap due to variation of tolerance) m is provided between an inner wall of the frame section 32 and an outer peripheral surface of the circuit board 3, for smoothly carrying out arrangement of the circuit board 3 into the frame section 32. In the example shown in FIG. 5A, a support portion 40 is provided in the frame section 32. The support portion 40 supports the circuit board 3 from a lower side. The support portion 40 has a height smaller than a height of the frame section 32. The circuit board 3 is arranged in the frame section 32 while being supported by the support portion 40. The circuit board 3 is arranged at a position spaced apart from a front surface of a mother board 12.
Referring to FIGS. 6A and 6B, the circuit module 31 is mounted on the mother board 12 when being used. The frame section 32 is vertically arranged on the mother board 12. For example, an attachment portion 36 protruding from a lower end of the frame section 32 is inserted into a hole 37 formed in the mother board 12, and is fixed to the mother board 12 by soldering, etc. Alternatively, referring to FIG. 6B, attachment portions 38 and 41 protrude outward from the frame section 32. The attachment portion 38 is fixed to the mother board 12 via solder 39. Also, the attachment portion 41 is fixed to the mother board 12 by a screw 43 inserted into screw holes 42 and 44.
Also, a pin terminal (not shown) protrudes from a back surface of the circuit board 3. The pin terminal is inserted into a through hole formed in the mother board 12 and is soldered at a back surface of the mother board 12. Accordingly, the electric circuit of the circuit board 3 is electrically connected with a circuit of the mother board 12 (for example, see Japanese Unexamined Patent Application Publication No. 61-13691, Japanese Unexamined Utility Model Registration Application Publication No. 5-18096, and Japanese Unexamined Patent Application Publication No. 2003-60376).
It is desirable to easily connect the circuit module with the mother board 12 by a fewer number of steps. If the circuit module 31 is electrically connected with the mother board 12 by inserting the pin terminal provided at the circuit board 3 into the hole of the mother board 12 and soldering the pin terminal, such connection is troublesome work, resulting in a low working efficiency. Thus, a product formed by arranging the circuit module 31 on the mother board 12 may be increased in cost.